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Old Oct 30, 2003, 9:57 PM   #1
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Default Look At These Shots. Why Does This Happen?

I'm finding that indoor shots taken with my 10D seem to have a reddish cast to them as seen in the following examples. Is this suppose to happen? These shots were taken on my kitchen counter which is white. The kitchen has flourescent dome lighting. (Other shots taken with tungsten lighting also have this reddish hue).

The first shot was set at AWB, the second shot at FlourescentWB, and the third KelvinWB. It's no big deal since I can color correct in PS but I was curious if others on this forum experienced the same.


http://www.onlinephotographers.com/g...toWB.sized.jpg


http://www.onlinephotographers.com/g...orWB.sized.jpg

http://www.onlinephotographers.com/g...inWB.sized.jpg
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Old Oct 30, 2003, 10:42 PM   #2
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My guess would have been down the direction you already went. White balance. Auto is usually close, but not always right.

What lens were you using and what fstop was it at? Some really bad lenses (or using a really crazy fstop) can create a color cast.

I'm not sure I know what "KelvinWB" is. Do you mean using a picture of a grey card to set the color temp?

Maybe someone else has some ideas?

Eric
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Old Oct 30, 2003, 10:48 PM   #3
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Eric, I used two different lenses both produced very similar results. Tamron SP AF 28-75mm F/2.8 and EF 24-85mm. The reddish hue appeared in both cases. The 10D's white balance settings include a Kelvin setting.
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Old Oct 31, 2003, 5:01 AM   #4
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FYI

AWB is a setting for daylight - Even the sun color temperature change throughout the day (early morning, midday, or sunset!) or even cloudy or hazy! This is slightly different from the fixed Daylight setting (5200 K)which do not compensate for the varying daytime color temperature but useful for people like me who use KR1.x warming filters (ie the AWB setting will tend to neutralize them) instead of UV or Skylight in front of their lenses... 8)

Flourescent WB - is for flourescent tube type of lights or power miser light bulbs which tend also to be in the blueish cast (hence your shots are yellow/red)

Kelvin WB - is just a scale unit. While the other WB settings get you quickly to certain range of lighting color temperature... The Kelvin setting allows to you to dial-in the exact color temperature in increment of 100K (you can read this off a handheld colormeter or other equipments)

BTW the correct setting for the above shots should have been Tungsten (incandescent), or turn the flash on which will illuminate the subject with a more daylight compatible beam
Check the slow sync where you can combine the two lightings:
http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM


NB: The manual says Automatic WB should balance over the entire range (ie 3000-7000K), but like theses images have proven, "Automatic" is not that smart and can be fooled by the varying content of the scene... ops:
BTW Have you try White Balance bracketing (WB-BRT)? :P
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Old Oct 31, 2003, 9:03 AM   #5
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Eric,

Look in your Instruction Manual for the 10D under White Balance.
Under Custom White Balance there is a simple procedure to set the correct color temperature by shooting a piece of white paper under the same lighting conditions. Its page 52 in my manual. This should work fine for anything between 2000K and 10,000K which practically covers it all.
Ted
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Old Oct 31, 2003, 11:33 AM   #6
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I know what custom white balance is. I'd just never heard of it refered to as "Kelvin WB" before.

My experience for Auto WB is that it seems to work fairly well outside (differences in sunlight) and not great indoors. Picking the right WB for your interior lights will do a better job (setting it with a custom WB off a grey card is the best, I'd presume. Never done it.) I once experimented with shooting every white balance but custom and found that Auto was close, but still a bit off.

Eric
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Old Oct 31, 2003, 12:14 PM   #7
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Eric,
It is true that AutoWB will handle most cases and that tungsten will come close to solving Steve's problem. I would use Custom WB under these conditions because it is more accurate.
Kelvin WB is only useful if you are using a color temperature meter and know the degrees Kelvin temperature.
Under Custom WB the 10D becomes a color temperature meter you shoot a white surface like a piece of white paper(not a grey card). When you use that image as a reference the camera will set the white balance correctly. Standard settings such as Flourescent and Tungsten are only approximations because many lamps of the same type will vary in color temperature.
Ted
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Old Oct 31, 2003, 7:24 PM   #8
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how does one set the custom WB?

Should you use a grey card or use a white object?
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Old Oct 31, 2003, 7:53 PM   #9
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A grey card is used to set the exposure and not for white balancing! (Ted described above correctly)

... One thing I would add is you can actually take several WB with various white images and select them afterward as you please either on the 10D or the Digital rebel when it's time to set the WB... ie you can have more than one white balance frame to select from. 8)
For example shoot the above piece of white paper in the kitchen, in your living room, and another in the basement... You now have three WB customized to the lightings of each particular room! :lol: :lol: :lol:
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Old Oct 31, 2003, 10:11 PM   #10
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oops, I missed Ted's reply. I didn't think that a grey card was the right thing to use...

my bad
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